Apparatus and method for forming cartons

ABSTRACT

An apparatus for forming cartons comprises feeding means, including a pivoted suction cup and cooperating vacuum belt conveying means, for individually feeding carton blanks to a forming means. Such forming means comprises a rotary table having a plurality of female forming dies radially positioned thereon. A ram-type male die is reciprocally mounted above the table to cooperate with each forming die to form the carton blank into tray form. Gas burner type nozzle means are mounted adjacent to the table to discharge heated air onto partially folded corners of a polyethylene-coated carton blank prior to when it is fully formed in the forming die. After the corners are compressed and sealed, stripping means engage the formed carton to move it onto a discharge conveyor.

United States Patent Le Febvre et al.

[ Mar. 14, 1972 [54] APPARATUS AND METHOD FOR 3,303,761 2/1967 Monroe 93/59 FORMING CARTONS 3,331,728 7/1967 Lane ..93/58 3,342,115 9 1967 Rein ke ..93/51 [72] Inventors: Alfred B. Le Febvre, Danville; Helmut E. 3 364 825 [$1968 gamzgarmer '93/59 f g" g w g 3,421,416 1/1969 Benzon-Petersen .93/5 1.1 2 3 3,456,564 7/1969 McCandless "193/59 3,511,139 5/1970 Edkvist ....93/51 [73] Assignee: Fibreboard Corporation, San Francisco, 3,533,332 10/1970 Young 3 Calif. Primary Examiner--Wayne A. Morse, J r. [22] Flled 1970 Attorney-Fryer, Tjensvold, Feix, Phillips 8!. Lempio [21] Appl. No.: 32,836

{57] ABSTRACT 1 3/36 MM, 93/391 P, An apparatus for forming cartons comprises feeding means, 93/59 ES, 93/ 93/59 93/84 FF including a pivoted suction cup and cooperating vacuum belt [5 Ill. Clconveying eans for feeding carton blanks to a [58] Field of Search ..93/36 MM, 51, 59, 84 FF, 39.1 P; f i means s f i means comprises a rotary tab; 269/21 having a plurality of female forming dies radially positioned thereon. A ram-type male die is reciprocally mounted above [56] References cued the table to cooperate with each forming die to form the car- UNITED STATES PATENTS ton blank into tray form. Gas burner type nozzle means are I mounted ad acent to the table to d1scharge heated a1r onto 2,414,574 1/1947 W1ll1ams 269/21 X partially folded comers of a polyethylene-coated carton blank 2, 1/1952 prior to when it is fully formed in the lforming die. After the 2,993,630 9/ 1961 p f X corners are compressed and sealed, stripping means engage 3,000,275 9/ 1961 Sevlson -93/51 the formed carton to move it onto a discharge conveyor. 3,062,105 11/1962 Oxborrow.. .....93/5l 3,187,648 6/1965 Tserpes 93/59 21 Claims, 18 Drawing Figures 2| 6 P x o 0 l 24 7! s a? 27 a1 70 so 6 c 48 Q n 93 Patented March 14,, R972 9 Sheets-Sheet 1 I03 I04 I05 m ammmd Wmmh 11% 111T 9 Sheets-Sheet 4 mented arch 9 Sheets-Sheet 5 atented March 35:

9 Sheets-Sheet 6 Mammal March 14,, 1%72 9 Sheets-Sheet 7 Pmmmd March 14, 1%?2 9 Sheets-Sheet 8 Pammmihedl March 1141 1'? 9 Sheets-Sheet 9 APPARATUS AND METHOD FOR FORMING CARTONS BACKGROUND OF THE INVENTION This invention relates to the packaging arts and more particularly relates to an apparatus and method for forming a flattened paperboard carton blank into tray or receptacle form adapted to have frozen foods or the like packaged therein. Such forming normally gives rise to numerous problems, such as an inability to assure tightly sealed corner closures at high speeds. In addition to the leakage and contamination problems arising therefrom, increased cartoon forming speeds also tend to distort and scar the carton to distort and scar the carton to impair its appearance and structural integrity.

SUMMARY AND OBJECTS OF THIS INVENTION An object of this invention is to overcome the above, briefly described problems by providing an apparatus and method for expeditiously, efficiently and economically forming the tray or receptacle portion of a carton out of a flattened blank. The apparatus exhibits a number of novel combinations and subcombinations, including a carton blank feeding means comprising a movably mounted suction cup and cooperating vacuum belt conveying means for precisely conveying each blank to a carton forming means. The carton forming means comprises a rotary table having at least one forming or female die positioned thereon to have the blank formed therein by a cooperating ram-type male die reciprocally mounted above the table. During formation of the blank in the cooperating dies, a heated fluid is discharged onto comers of the blank to activate a pre-coated adhesive prior to final sealing.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects of this invention will become apparent from the following description and accompanying drawings wherein:

FIG. 1 is an isometric view of a preferred apparatus embodiment of this invention;

FIG. 2 is a top plan view of a carton blank, taken in the direction of arrows 2-2 in FIG. 7, adapted to be formed into the carton shown in FIGS. 3-5 by the FIG. 1 apparatus;

FIG. 6 is a partially sectioned and enlarged top plan view of the FIG. 1 apparatus, taken in the direction of arrows 6-6 in FIG. 1;

FIG. 7 is an enlarged sectional view taken in the direction of arrows 7-7 in FIG. 6 with parts broken-away for clarification purposes;

FIG. 8 is a sectional view taken in the direction of arrows 8-8 in FIG. 15;

FIGS. 9 and 10 schematically illustrate portions of drive systems employed in the FIG. I apparatus, with FIG. 9 being taken in the direction of arrows 9-9 in FIG. 6;

FIGS. 11 and 12 schematically illustrate the FIG. 1 apparatus in various modes of its carton forming operation;

FIGS. 13 and 14 are enlarged, top plan views of a forming die employed in the FIG. 1 apparatus with a carton blank being sequentially positioned thereon;

FIG. 15 is an enlarged, sectional view generally taken in the direction of arrows 15-15 in FIG. 6;

FIG. 16 is a partially sectioned and enlarged isometric view generally taken in the direction of arrows 16-16 in FIG. 6, illustrating carton stripping means employed in the FIG. 1 apparatus;

FIG. I7 is a view generally taken in the direction of arrows 17-17 in FIGS. 6 and 16; and

FIG. I8 is a view taken in the direction of arrows 18-18 in FIG. 17.

DESCRIPTION OF PREFERRED APPARATUS EMBODIMENT The FIG. 1 apparatus comprises, in series, a feeding station 20 for individually conveying carton blanks C to a forming station 21 and a discharge station 22 for removing the formed cartons therefrom. The FIG. 2 one-piece paperboard carton blank is preferably coated on both sides with a suitable laminant plastic coating, such as polyethylene, polyvinylldene chloride or other suitable heat sensitive coating which will reactivate (melt) at high temperatures such as 500 F. The blank may be suitably cut and scored to comprise a bottom panel P side panels P and P and front and rear panels P and P A top panel or cover flap F is hingedly connected at a scoreline to the top edge of rear panel P whereas vertically disposed minor flaps F F and F are connected in a similar manner to panels P P and P respectively. A tearline T may be formed in the top and rear panels to define a removable tab adapted to be torn open to expose the cartons contents after the cover flap has been bonded to minor flaps F,- F to form a closed carton.

Gusset folds G G G and G are suitably constructed at each comer of the tray or receptacle portion of the carton to form sealed comer closures thereat. FIG. 3 illustrates partial formation of the blank whereas FIGS. 4 and 5 illustrate complete formation of such tray portion by the FIG. 1 apparatus.

Referring to FIGS. 1, 2, 6 and 7, feeding station 20 includes a carton magazine 23 comprising opposed pairs of upright posts 24 and 25. The posts are secured to frame 26 of the apparatus and adapted to retain a plurality of stacked carton blanks C therein along with the tapered ends of spaced, stationary supports 27. Each of the supports underlie and engage marginal rear edge portions of the lowermost blank to aid in supporting the blanks in the magazine. The tapered ends of such supports are suitably positioned to permit the lowermost blank to be readily disengaged therefrom by removal means 28, comprising a flexible suction cup 29.

A flexible conduit 30 may be operatively connected to the suction cup in a conventional manner to communicate a negative pressure or vacuum (e.g., 5p.s.i.) thereto by means of a conventional vacuum source and control means 300 (FIG. 7). The vacuum cup is mounted on an arm 32 attached to a stub shaft 33 pivotally mounted on the frame of the apparatus. A rod 34 is attached at its upper end to the stub shaft to form a bellcrank arrangement with lever 32.

The lower end of the rod is slidably mounted in a sleeve member 35 pivotally mounted on a crank 36 by a pivot pin 37 (FIG. 9). The crank is attached to a continuously rotating drive shaft 38 which is driven by a sprocket 39. The gears are continuously driven by an endless chain 40 suitably mounted on sprockets 41-45. Sprocket 45 is mounted on a power shaft 46 which is driven via conventional gear type transmission means by a main drive motor 47 of the apparatus (FIG. 10).

Thus it can be seen that actuation of motor 47 and drive shaft 46 will function to continuously move chain 40 to rotate sprocket 37. Upon simultaneous rotation of crank 36, sleeve member 35 will reciprocate on rod 34 to oscillate stub shaft 33. Thus arm 32 will be pivoted between its dotted and solid line positions illustrated in FIGS. 7 and 9 to continuously remove a lowermost carton blank from the magazine. A stationary, laterally positioned guide wire 48 engages the edges of the blanks for aiding in such removal function.

The feeding station further includes vacuum belt conveying means shown as comprising spaced endless belts 50 and 51 (FIGS. 1, 6 and 7) having apertures 52 and 53 formed therethrough, respectively. Belt 50, for example, is mounted on a drive pulley 54 and idler pulley 55, the drive pulley being mounted on a drive axle 56 which is common to sprocket 41 (FIG. 9). Belt 51 is mounted in a like :manner to also be driven by drive axle 56.

A hollow stationary support means or plate 57 is mounted below belt 50 to support same (FIGS 6 and 7). The portions of the support means engaging the belt may have a Teflon or like coating formed thereon to lower the coefficient of friction therebetween. The support means forms vacuum chambers 58 therein adapted to be evacuated by means of a conduit 59 communicating therewith. Such conduit communicates with vacuum source 31 which may comprise a conventional centrifugal pump or the like (FIG. 7). Vacuum belt 51 is supported on a similar support means or plate in a like manner.

Thus it can be seen that when the lowermost flat carton blank C, having its forward edge only normally resting on belts 50 and 51, is pulled downwardly onto the belts by vacuum cup 29 that such blank will be subjected to vacuum via apertures 52 and 53. The suction cup disengages the blank automatically due to the intermittent action of valve means (not shown) of control means 30a when it descends below the belts. Thus the belts will function to grasp and move the blank toward forming station 21 and between a pair of flexible pinch belts 60 and 61 and a pair of nip rolls 62 and 63.

As best shown in FIGS. 6 and 7, the pinch belts are each suitably mounted on a plurality of spaced idler and takeup pulleys and are driven by powered pulleys 64 and 65, respectively. Pulley 64 is driven by a shaft 66, common to sprocket 43 (FIG. 9), whereas pulley 65 is driven by a shaft 67 which is common to sprocket 44. Nip rolls 62 and 64 are suitably mounted on and driven by shafts 66 and 67, respectively.

Referring to FIG. 6, the pinch belts and nip rolls deliver the carton blank to a forming or female die 70 mounted on and having its forming chamber extending completely through a rotary table 71. Although eight such dies are shown, it should be understood that any desired number thereof may be employed. As shown in FIG. the horizontally disposed table is secured to an upstanding hollow column 72 rotatably mounted on spaced roller bearing assemblies 73 (one shown).

As schematically illustrated in FIG. 10, rotating column 72 is attached to and driven by a bull sprocket 74 which, in turn, is driven by an endless chain 75. The chain is further trained on and driven by a sprocket 76 secured to a drive shaft 77. The drive shaft is suitably driven by drive shaft 46 which is driven by main electrical drive motor 47 of the apparatus.

Referring to FIGS. 13 and 14, stationary fingerlike guide wires 80, 81 and 82 are suitably positioned to elevate and guide the blank onto the forming die. Flap I of the carton blank engages under a locating plate 83 of locating means 83-88 to initiate the locating function. Upon continued rotation of the table flap F will engage and be guided by locating button 84 whereas flap F will subsequently engage locating button 85. Locating pins 86, 87 and 88 will assume the positions illustrated in FIG. 14, relative to the blank, with locating pin 88 functioning as the primary means for completely removing the blank from pinch belts 60 and 61.

Referring to FIGS. 11 and 12, turntable 71 and its associated forming mechanisms have been divided into sub-stations I-VIII for explanation purposes. The upper heavy dotted line 89 schematically represents a cam profile exhibited during the carton forming operation. The following operations approximately occur at such stations:

I. Flattened carton blank C initiates registry over forming die 70;

II. A male die 90 cooperates with die 70 to form a pair of die means for partially folding the carton blank therein;

(III) The carton blank is further folded to ready gusset folds G -G thereof (FIG. 3) for bonding;

(IV) Heat sealing means 91 and 92 discharge heated air onto the gusset folds;

(V) Die 90 begins its descent to compress gusset folds together to form tightly sealed comers;

(VI) Die 90 moves downwardly, below the table, to permit the formed carton to be ejected onto a discharge conveyor 93;

(VII) Die 90 moves vertically upwardly; and

(VIII) Die 90 is fully repositioned for a second carton forming operation.

Referring to FIG. 8, each bank of heaters 91 and 92 may be simultaneously ignited by means of a spark plug 94 exposed to the combustion chamber of one of the end heaters. Conduits then communicate the ignited gaseous fuel mixture to all of the heaters. An ignition control system 95, comprising an onenergizes the spark plug.

Referring to FIGS. 1 and 15, each male die is secured to the end of a rod 96, reciprocally mounted in spaced bearing journals 97 and 98. Such bearing journals are secured to a bifurcated arm 99 which is, in turn, secured to rotatable column 72. A bracket 100 is attached to the upper end of the rod and has a roller 101 and a pair of rollers 102 rotatably mounted thereon.

Roller 101 is guided in its rotary movements by an endless cam track 103, defining cam profile 89 in FIGS. 11 and 12, FORMED between spaced stationary bars 104 and 105. The cam track and rod 96 comprise actuating means for linearly moving male die 90 into mating relationship with female die 70 for folding an forming the carton blank therein. Inboard rollers 102 preferably engage opposite sides of a vertically disposed guide means or bar 106 mounted on a bracket 107 attached to arm 99. Such guide bar positively assures that rod 96 will only move vertically, without incurring any rotational or other extraneous movement.

As further illustrated in FIG. 15, dies 70 and 90 are each preferably completely jacketed therearound with chamber means 108 and 109, respectively, for circulating a coolant such as water therethrough for heat-sink purposes. As schematically illustrated therein, a pump 110 and valve 111 may be utilized to selectively circulate and communicate such coolant through conduits 112, 113 and 114 and to chamber 109 of the male die. Such fluid is then communicated from chamber 109 to chamber 108 of the female die via conduits 115 and 116. A conduit 117 returns the fluid to a heat exchanger 118 for recirculation purposes by means of pump 110.

Referring to FIGS. 6 and 15, opposed heat sealing means 91 and 92 each comprise a plurality of identical gas burner type nozzle means or heaters 120 positioned in arcuate arrays adjacent to table 71. The heaters of heating means 91 and 92 are fixedly mounted on stationary conduits 121 and 122, respectively, which function to communicate a combustible gaseous fluid, such as a commercially available natural gas-air mixture, to the heaters. Such heaters and a conventional fuel source and control means thereof are fully disclosed in US. Pat. application Ser. No. 869,193 for Apparatus and Method for Heat Sealing Cartons, filed on Oct. 24, 1969 by George Schafer et al. Such application is assigned to the Assignee of this application.

As described therein each heater may be of the type identified as model N0. SH-2 and manufactured by Selas Corp. of America. Such heater comprises a metallic housing having a suitable refractory and insulative material formed therein to define a combustion chamber. As above stated, ignition means 94 and 95 function to ignite the gaseous fuel communicated to the combustion chambers by conduits 121 and 122. Due to well-known combustion and heat transfer phenomena, including the expansion of the ignited gas-air mixture, a heated fluid stream 123 (FIG. 15) is discharged from each heater and directed toward gusset folds G,G The heated fluid is discharged in sufficient volumes and maintained within acceptable temperature and pressure ranges to activate (melt) the adhesive (e.g., polyethylene), but to prevent carton distortion or scorching.

Through stations V and VI (FIGS. 6 and 12), cam track 103 (FIG. 15) functions to move rod 96 downwardly to fully fold and form the gusset folds to bond or seal them together. At stations VI and VII the formed carton is discharged onto conveyor means 93. Rod 96 thereafter moves upwardly through stations VII and VIII to ready male die 90 for a subsequent carton forming operation.

Referring to FIGS. 16-18, a carton stripping means 124 is preferably utilized to positively strip the carton off each male die 90. The stripping means comprises a bracket 125 bolted or otherwise suitably secured to table 71. Upstanding guide bars 126 and 127 are secured to the bracket and slidably mount a reciprocating member 128 thereon. The member comprises parallel arms 129 and 130 secured thereto for engagement with the top edges of side flaps F and F of the carton.

Reciprocal movement is imparted to member 1241 by means of a pin 131 positioned in a lost motion slot 132 formed through the member. The pin is secured to a first lever arm 133 of a bellcrank mechanism further comprising a rockable shaft 134 having arm 133 and a second lever arm 135 attached to opposite ends thereof. A roller 136 is rotatably mounted on a pivot pin 137, secured to arm 135, to engage a stationary cam track 133 mounted below table 71.

A coil portion 139 of a biasing spring is mounted on shaft 134 and has one end anchored to a housing 140. The housing, journaling shaft 134 therein, is secured to bracket 125. The other end or finger portion 141 of the spring engages arm 135 to constantly urge roller 136 against cam track 138.

Thus it can be seen that upon rotation of table 71, through stations VI and VII, that the roller will engage the cam track to rock shaft 134 to move member 128 downwardly to its dotted lined position in FIGS. 16 and 17. Thus arms 129 and 130 will engage flaps F and F of the carton to strip it off male die 90. The formed carton will then be deposited onto moving conveyor 93 wherefrom it may be transported to a frozen food filling and final sealing apparatus. Suitable drive mechanisms (not shown) may be employed to drive and conveyor via the apparatus main drive motor.

What is claimed is:

1. An apparatus for forming cartons comprising feeding, forming and discharge stations arranged in series, said feeding station comprising a magazine for retaining a plurality of flattened carton blanks therein, removal means for individually removing said carton blanks from said magazine and conveying means for receiving said blanks from said removal means and for transferring each blank tangentially to a rotary table of said forming station, said forming station further comprising at least one pair of cooperating male and female die means disposed adjacent to the periphery of said table for folding and forming a carton therein and actuating means for moving said male and female die means into mating relationship to form said carton upon rotation of said table, said male die means reciprocally mounted above said table and said female die means fixedly mounted on said table, and locating means positioned about said female die means and cooperating with said conveying means for receiving and guiding a tangentially fed carton blank and for pivoting such carton blank into precise registry over said female die means upon rotation of said table.

2. The invention of claim 1 wherein said female forming die defines a forming chamber extending completely through said rotary table.

3. The invention of claim 1 wherein at least one of said female forming and male dies is jacketed therearound with a chamber means and means for circulating a coolant through said chamber means for heat sink purposes.

4. The invention of claim 3 wherein each of said female forming and male dies has one of said chamber means jacketed therearound.

5. The invention of claim 1 wherein said actuating means comprises means forming a stationary cam track mounted above said table and means attached to said male die and guided by said cam track for linearly moving said male die relative to said female forming die.

6. The invention of claim 5 wherein said cam track is endless.

7. The invention of claim 5 further comprising guide means operatively associated with said actuating means for guiding linear movements of said male die.

8. The invention of claim 1 wherein. a plurality of said male and female die means are radially disposed about said table.

9. The invention of claim 1 wherein said conveying means comprises at least one perforated belt movably mounted adjacent to said removal means, a support means at least partially mounting said perforated belt thereon, chamber means formed in said support means to be exposed to said perforated belt and means for drawing a vacuum in said chamber means.

10. The invention of claim 9 further comprising additional conveying means mounted between said first-mentioned conveying means and said table for receiving said blanks from said first-mentioned conveying means and for transferring them to said table.

11. The invention of claim 9 wherein said removal means comprises a suction cup movably mounted adjacent to said magazine.

12. The invention of claim 1 wherein said forming station further comprises nozzle means mounted adjacent to said table for discharging a heated fluid onto portions of an adhesively treated carton blank prior to its formation by said cooperating male and female die means.

13. The invention of claim 12 wherein said nozzle means comprises at least one set of heaters circularly disposed adjacent to said female die means for discharging said heated fluid theretowards upon rotation of said table.

14. The invention of claim 13 wherein two sets of said heaters are fixedly mounted adjacent to said female die means, said sets positioned to oppose each other.

15. The invention of claim 13 wherein each of said heaters comprises a combustion chamber, means for communicating a gaseous fuel to said combustion chamber, means for communicating said combustion chambers with each other and ignition means for substantially simultaneously igniting said gaseous fuel in all of said combustion chambers.

16. The invention of claim 1 wherein female die is formed completely through said table and said discharge station comprises stripping means positioned beneath said table for stripping a formed carton otf said male die means when it descends through said female die means.

17 The invention of claim 16 wherein said discharge station further comprises a discharge conveyor for receiving said formed carton.

18. A method for forming a carton comprising the steps of conveying a flattened carton blank tangentially with respect to a rotating table,

positioning said flattened carton blank over a hollow female forming die by engaging edges. thereof with locating means disposed about said female forming die, said female forming die being fixedly mounted on said rotary table adjacent to the periphery thereof, and

rotating said table while simultaneously moving a male die into said female forming die to form said carton therein.

19. The invention of claim 18 further comprising the step of discharging a heated fluid onto corner folds of said carton prior to when said carton is fully formed by said dies to seal said corner folds together.

20. The invention of claim 18 further comprising the steps of moving said male die and formed carton below said table and stripping said carton off said male die.

21. The invention of claim 18 further comprising the steps of conveying said flattened carton blank toward said table on a belt and simultaneously subjecting said carton blank to a vacuum to hold it on said belt. 

1. An apparatus for forming cartons comprising feeding, forming and discharge stations arranged in series, said feeding station comprising a magazine for retaining a plurality of flattened carton blanks therein, removal means for individUally removing said carton blanks from said magazine and conveying means for receiving said blanks from said removal means and for transferring each blank tangentially to a rotary table of said forming station, said forming station further comprising at least one pair of cooperating male and female die means disposed adjacent to the periphery of said table for folding and forming a carton therein and actuating means for moving said male and female die means into mating relationship to form said carton upon rotation of said table, said male die means reciprocally mounted above said table and said female die means fixedly mounted on said table, and locating means positioned about said female die means and cooperating with said conveying means for receiving and guiding a tangentially fed carton blank and for pivoting such carton blank into precise registery over said female die means upon rotation of said table.
 2. The invention of claim 1 wherein said female forming die defines a forming chamber extending completely through said rotary table.
 3. The invention of claim 1 wherein at least one of said female forming and male dies is jacketed therearound with a chamber means and means for circulating a coolant through said chamber means for heat sink purposes.
 4. The invention of claim 3 wherein each of said female forming and male dies has one of said chamber means jacketed therearound.
 5. The invention of claim 1 wherein said actuating means comprises means forming a stationary cam track mounted above said table and means attached to said male die and guided by said cam track for linearly moving said male die relative to said female forming die.
 6. The invention of claim 5 wherein said cam track is endless.
 7. The invention of claim 5 further comprising guide means operatively associated with said actuating means for guiding linear movements of said male die.
 8. The invention of claim 1 wherein a plurality of said male and female die means are radially disposed about said table.
 9. The invention of claim 1 wherein said conveying means comprises at least one perforated belt movably mounted adjacent to said removal means, a support means at least partially mounting said perforated belt thereon, chamber means formed in said support means to be exposed to said perforated belt and means for drawing a vacuum in said chamber means.
 10. The invention of claim 9 further comprising additional conveying means mounted between said first-mentioned conveying means and said table for receiving said blanks from said first-mentioned conveying means and for transferring them to said table.
 11. The invention of claim 9 wherein said removal means comprises a suction cup movably mounted adjacent to said magazine.
 12. The invention of claim 1 wherein said forming station further comprises nozzle means mounted adjacent to said table for discharging a heated fluid onto portions of an adhesively treated carton blank prior to its formation by said cooperating male and female die means.
 13. The invention of claim 12 wherein said nozzle means comprises at least one set of heaters circularly disposed adjacent to said female die means for discharging said heated fluid theretowards upon rotation of said table.
 14. The invention of claim 13 wherein two sets of said heaters are fixedly mounted adjacent to said female die means, said sets positioned to oppose each other.
 15. The invention of claim 13 wherein each of said heaters comprises a combustion chamber, means for communicating a gaseous fuel to said combustion chamber, means for communicating said combustion chambers with each other and ignition means for substantially simultaneously igniting said gaseous fuel in all of said combustion chambers.
 16. The invention of claim 1 wherein female die is formed completely through said table and said discharge station comprises stripping means positioned beneath said table for stripping a formed carton off said male die means when it descends through said female die meanS.
 17. The invention of claim 16 wherein said discharge station further comprises a discharge conveyor for receiving said formed carton.
 18. A method for forming a carton comprising the steps of conveying a flattened carton blank tangentially with respect to a rotating table, positioning said flattened carton blank over a hollow female forming die by engaging edges thereof with locating means disposed about said female forming die, said female forming die being fixedly mounted on said rotary table adjacent to the periphery thereof, and rotating said table while simultaneously moving a male die into said female forming die to form said carton therein.
 19. The invention of claim 18 further comprising the step of discharging a heated fluid onto corner folds of said carton prior to when said carton is fully formed by said dies to seal said corner folds together.
 20. The invention of claim 18 further comprising the steps of moving said male die and formed carton below said table and stripping said carton off said male die.
 21. The invention of claim 18 further comprising the steps of conveying said flattened carton blank toward said table on a belt and simultaneously subjecting said carton blank to a vacuum to hold it on said belt. 